Public health investigators are using DNA “fingerprints” of E. coli bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that may be part of this outbreak. They are using data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.
The type of bacteria responsible for this outbreak is among those referred to as Shiga toxin-producing E. coli or STEC. STEC bacteria are grouped by serogroups (e.g., O157 or O145). The STEC serogroup found most commonly in U.S. patients is E. coli O157.
A total of 28 ill persons infected with the outbreak strain of STEC O157:H7 have been reported from five states. The number of ill people identified in each state with the outbreak strain is as follows: Connecticut (2), Massachusetts (2), New York (22), Pennsylvania (1), and Virginia (1).
Among persons for whom information is available, illness onset dates range from October 18, 2012 to November 3, 2012. Ill persons range in age from 4 years to 66 years, with a median age of 24 years. Sixty-eight percent of ill persons are female. Among 24 ill persons with available information, 10 (42%) reported being hospitalized. Two ill persons have developed hemolytic uremic syndrome, a type of kidney failure. No deaths have been reported.
This PFGE pattern has very rarely been seen before in PulseNet. It has been seen only 7 times prior to this outbreak. Illnesses that occurred after October 30, 2012 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This outbreak can be visually described with a chart showing the number of persons who became ill each day.
